Well, his ultimate is an execution, and therefore when he kills a enemy with it, it should lower the cooldown by around 10-20 seconds. Scaling with +10 seconds reduction of it each time it's ranked up. If Darius's ultimate can have a cooldown reset at rank 3, and be able to cast his ultimate within a frame of 20 seconds after killing someone with it, I feel that Garen should have the similar power he has with his main execution tool.
Lord Dusteon1 votesDarius also doesn't have a 2.5 second hard CC, 20% bonus armor and magic resist, damage reduction, or a constant Black Cleaver shred AoE.
JusticePauldrons1 votesHard cc...silence is not hard cc. Hard cc prevents movement and stops control of a character. This means stuns, snares taunts etc. Silence is soft cc. Darius' pull? That is hard cc.
Snake Town1 votesI think I have a better solution. Given garen a seventh item slot that can only hold a deathfire grasp. BRING BACK THE WIZARD!!!!! 
9kPluzZ1 voteswhy make him a DaRIUS Clone? Jinx, Lee, and Caitlyn's Exacutes don't do that... Also Garen is Op as fuk right now.
JustOneWolf1 votesIt's not a clone, If I wanted that I would've said rank 3 give his ultimate back when he kills someone. Also Jinx, and Lee ult's aren't executions.